Community Forums

RV Vagabond · 02-27-2016, 10:07 AM

Has anyone wired their air conditioners through the inverter? Gone With The Wynns did it and it worked fine as long as solar panels were constantly charging the batteries. I wonder how well it would work in the long term.

Davdeb1 · 02-27-2016, 10:16 AM

You need a massive amount of solar, and worse yet a huge battery bank. If you read it they also commented it could only be used short periods of time. The Wynn's don't pay for any of this stuff, short term lease the vehicles, and get all sorts of free stuff from the manufacturer. I think they've had 3 new RVs in the last 4-5 years.
The reality is, it can be done but at what cost?

Selah · 02-27-2016, 01:13 PM

The Coleman Mach 8 uses 1657 running watts and 2017 watts. That's about 15 amps at 110 volt or 138 amps at 12 volt.

asuperheat · 02-28-2016, 05:35 PM

Just not practical, better off running a generator if you need it. You would need a serious inverter and battery bank. The starting current would be a lot higher than the running current.

marcham · 02-28-2016, 05:40 PM

A rooftop swamp cooler would be a better option if you need to cool from solar /batteries , but then you'll need a large water supply and they don't work in high humidity.

http://www.turbokool.com

Cat320 · 02-29-2016, 05:49 PM

Quote:

Originally Posted by asuperheat

Just not practical, better off running a generator if you need it. You would need a serious inverter and battery bank. The starting current would be a lot higher than the running current.

Agree...never work.

RV Vagabond · 03-01-2016, 12:18 AM

Quote:

Originally Posted by Cat320

Agree...never work.

Watch this and tell me it will never work
Off Grid Solar Powered RV Air Conditioning - Is it Possible? - Gone With The Wynns

Mr_D · 03-01-2016, 12:41 AM

It can be done. One of the options for our MH (we don't have it) was to be able to run one heat pump off the inverter. They added another 3000 watt PS inverter and 2 add'l 8D batteries (for a total of 8) as well as a bigger alternator. Even then it wouldn't run for more than a couple of hours, if that.
In our 2000 Dutch Star we had CW wire in a bigger inverter. When done we could run one 13.5 heat pump for about 20 min off two U-2200 batteries, then we got the low voltage alarm

Scatterbrain · 03-01-2016, 01:01 AM

Quote:

Originally Posted by RV Vagabond

Watch this and tell me it will never work
Off Grid Solar Powered RV Air Conditioning - Is it Possible? - Gone With The Wynns

It's not that it isn't possible, it's that it requires a lot of investment, and the return is minimal. Just run the generator. Figure the cost of the batteries (that kind of sustained, high amperage discharge is better suited to lithium), inverters, a larger collections of solar panels, solar power controllers, etc. Then bear in mind that even with all of that you can't go running the A/C willy-nilly, you have to be careful about when you run it and for how long. Think about how long you'd have to run that A/C before the cost of the solar set up became less than the cost of the fuel for the generator. It's likely that the math will show that you'd have moved on to your next rig before the solar set up showed dividends.

nothermark · 03-01-2016, 01:13 AM

The problem really comes down to possible vs rational.

They ran their A/C for several hours on a combination of battery and solar. If you paid attention they were using more power than the solar setup was providing thus they were depleting their hugely oversize battery bank all the time the A/C was running. That was parked with the cells up and presumable optimized for orientation.

Most of us see that as an example of a way cubic dollars of equipment can make an interesting demonstration. That is all it is as the setup is not sustainable unless you run the generator or only want an hour or two of A/C so the solar can put back the power taken from the batteries.

The only way to get it sustainable is to put out enough panels to cover the full usage plus some to do other things. That will not fit on the roof but is possible for a semi permanent setup. That is both a lot of money and a lot of trouble for a motor home. OTOH if you have a remote building you want to run solar powered A/C on you could do it with enough money. I have even seen some numbers that indicate the cost may be converging to where it is worth putting up solar panels to avoid paying for A/C power even when grid connected. The difference is in dollars and not being limited to the MH roof.

cwsqbm · 03-01-2016, 03:36 AM

Quote:

Originally Posted by nothermark

Most of us see that as an example of a way cubic dollars of equipment can make an interesting demonstration. That is all it is as the setup is not sustainable unless you run the generator or only want an hour or two of A/C so the solar can put back the power taken from the batteries.
.

Newmar offers a battery/inverter powered A/C for their top-of-the-line King Aire. With that option, it gets 8(!) ADDITIONAL batteries and a dedicated inverter that is capable of running one of its three A/C units for about 8 hours. Solar isn't the issue, but instead being able to run the A/C overnight during no-generator hours. Its part of a $4000 option, and that's without any solar to recharge the batteries. Enough solar wouldn't fit on a 45' roof with all the other stuff (A/Cs, vents, satellite dish).

Dr4Film · 03-01-2016, 04:47 AM

Of course it is possible to wire the A/C to the Inverter circuit BUT is it practical? Nope, here's why.

Assuming you have a typical RV setup with 4 - 6 volt Golf Cart batteries for house use and Inverter use, that means you will have 450 amp hours of battery BUT can only use 225 amp hours, 50% SOC. When running one A/C on your Inverter without calculating startup amps you will deplete your batteries in less than 2 hours then you're done.

So unless you are willing to install MANY batteries and a means of keeping them charged, in my estimation it is NOT practical.

However, you could purchase a small Energy Saver window A/C for the bedroom wired to the Inverter which would run much longer possibly even over night providing that there wasn't anything else needing the same battery power in your coach.

One Monacoers member has done just that successfully.

Dr4Film ----- Richard

mojoracing · 03-01-2016, 06:56 AM

"The problem really comes down to possible vs rational." As with everything the Wynns do, it is just not practical. When you consider the dollars spent it is not only impractical but the end result can be accomplished with systems already in place. Why be redundant when you can start your gen and run your AC to be comfortable. Solar systems simply are not at a point where convenience and practicality outweigh dollars. I could have all the solar in the world but it would do me absolutely no good while camping in Georgia between June and September. Sure I could run everything 12 volt and never run my gen or plug in but they would find my lifeless body on the floor of my 120 degree motorhome. Lets face it, boon docking in the fall and spring while living on solar is one thing but it still doesn't solve the reason we are all not tent camping.

DDDonkey · 03-01-2016, 03:45 PM

It can be done, the trucking industry has started doing it with stand alone A/C systems that run of batteries for 10 hours or more due to the idling laws, but is costly and adds some serious weight.

Electric APU | Battery-Based No Idle Systems for Sleeper Trucks and Day Cabs

Arctic Breeze Truck AC: 12V/DC air conditioning keeps cabs cool without wasting fuel

And there are others out there.